Skyscrapers were an efficient way to organize businesses within one building. Though skyscrapers were born in New York, the method called Chicago Construction, developed by Chicago architects and engineers between 1880 and 1883, provided the basic structural system for building modern steel-and-glass office towers.

In response to cholera and dysentery epidemics, the Chicago Board of Sewage Commissioners selected Ellis Chesbrough to design a new water system for the city. In Chesbrough's plan, clean water from the lake bottom would pour into intakes under a crib two miles into Lake Michigan, then into an underground tunnel to a water tower. From there, clean water would flow into the city's water mains.

In response to cholera and dysentery epidemics, the Chicago Board of Sewage Commissioners selected Ellis Sylvester Chesbrough to solve Chicago’s public health crisis. Chesbrough’s planned system relied on gravity flow, but downtown streets were too low to drain into the river. New sewers raised the city's streets as much as 10 feet. The challenge then was to raise the buildings.

Although the grain elevator was invented in Buffalo, the grain elevator system came into being in Chicago—the city built its first in 1848, and by 1858 twelve mammoth grain houses dominated its skyline. By 1861, Chicago's grain trade had increased to 50 million bushels annually -- a rise of over 48 million bushels in a decade -- supporting the city's boast that it fed the world.

By the mid-19th century, Chicago was a growing city encountering problems with its water supply and sewage disposal. Ellis Chesbrough was selected to solve Chicago’s public health crisis. Chesbrough’s solution: change the direction of the Chicago River. In 1871, the extraordinary feat of engineering was accomplished—the river now flowed west from Lake Michigan and down to the Illinois River.

An obsessed artist struggles against bankruptcy, public indifference, and a brutal terrain, to build the great American monument, Mount Rushmore. High on a granite cliff in South Dakota's Black Hills tower the huge carved faces of four American presidents: George Washington, Thomas Jefferson, Abraham Lincoln, and Theodore Roosevelt. Together they constitute the world's largest piece of sculpture.

An obsessed artist struggles against bankruptcy, public indifference, and a brutal terrain, to build the great American monument, Mount Rushmore. High on a granite cliff in South Dakota's Black Hills tower the huge carved faces of four American presidents: George Washington, Thomas Jefferson, Abraham Lincoln, and Theodore Roosevelt. Together they constitute the world's largest piece of sculpture.

After his workers had blasted off the surface rock of the mountain, Gutzon Borglum spent days and nights watching how the light and shadow landed on the mountain. This process ultimately made him decide to deviate from the original plan and shift 20 degrees. Borglum built a studio size model of Mount Rushmore and proceeded to enlarge the measurements on a scale to sculpt the mountain itself.

The Borglum family archives include some historic home movies, early color films of the mountain's sculpting in progress. See Gutzon and the workers in action as they struggle with winches, jackhammers -- and Mother Nature.

Since 1930, more than 50,000,000 people have visited Mount Rushmore, the biggest -- and arguably the most compelling -- monument on the face of the earth.

Gutzon Borglum and his team of workers were aware that there would be challenges to face during the sculpting of Mount Rushmore. While some of the faults were easy to identify, others were difficult to detect.

Even though the workers blasted down 60 feet to find carve-able rock, huge cracks took shape on the Jefferson face. Borglum used a special concoction of materials to fill in the cracks in Jefferson's head, costing additional time and money.

In 1927, the Mississippi River flooded from New Orleans to Illinois, leaving a million people homeless and leading to a major black migration to the North.

In 1927, the Mississippi River flooded from New Orleans to Illinois, leaving a million people homeless and leading to a major black migration to the North.

Footage from the 1927 flood. Clips include shots of workers along the Mississippi River enforcing the levees with sandbags, Secretary of Commerce Herbert Hoover surveying the damage, and aerial views of the flooding.

Cinematographer Boyd Estus talks about filming the Pioneer Zephyr exhibit at the Museum of Science and Industry in Chicago and the joys of shooting historical documentaries.

Home videos of Rockefeller family members at the family estate -- playing in the yard, learning to drive, swimming, and John D. Sr. arriving home.

John D. Rockefeller was the world's first billionaire and the most hated man in America. Watch the epic story of the man who monopolized oil.

In this exclusive interview, Princeton economist and New York Times columnist Paul Krugman discusses the relevance of the Rockefellers in today's business environment of mergers, monopolies, and the new "age of the heroic entrepreneur."

Robert Douglass served as Counsel and later Secretary to Governor Nelson Rockefeller from 1965-1972. He was sent to Attica during the uprising to represent the Governor and to help quell the riot and appease the inmates. Frank Smith was an inmate at the prison and acted as a guard during the uprising, trying to assure that none of the officials sent in to negotiate with the prisoners were harmed.